The present invention will be described with an example application for an Ethernet computer network peripheral device which couples a host computer system to a network of computers. In this example application, the Ethernet computer network peripheral device locally generates a reference clock frequency from a base clock frequency provided by the host computer system or the network of computers. However, from this example application, it should be appreciated by one of ordinary skill in the art of electronic systems design that the present invention may be used for locally generating a reference clock frequency at any electronic device from a base clock frequency provided by any base clock signal source that is external to the electronic device.
Referring to FIG. 1, a network of computers 100 includes a first computer 102, a second computer 104, a third computer 106, and a fourth computer 108 interconnected to each other via a linking network 110. A computer peripheral device 112 is within the first computer 102 to provide added functionality to the first computer 102. For example, this computer peripheral device 112 may be an Ethernet computer network peripheral device which allows the first computer 102 to communicate with the other computers 104, 106, and 108 via the linking network 110.
Such a computer peripheral device 112 includes timers for timing events of data transmission and reception and other types of events at the first computer 102 or at other parts of the network of computers 100. These timers require a respective reference clock signal having a respective reference frequency for timing such events. For example, an Ethernet computer network peripheral device may require a 1 MHZ (megahertz) reference clock signal for a 1 .mu.s (microsecond) timer and a 10 MHZ reference clock for a 0.1 .mu.s timer.
Although the computer peripheral device 112 needs reference clock signals for timing events, original clock signal generators may be costly to incorporate within the computer peripheral device 112. The host system of the first computer 102 typically has a base clock signal having a base frequency. Moreover, other parts of the network of computers 100 including the second computer 104, the third computer 106, the fourth computer 108, and the linking network 110 may include a respective base clock signal having a base frequency. Thus, it would be desirable to generate the reference clock signals for use within the computer peripheral device 112 from a base clock signal already available from a base clock signal source that is external to the computer peripheral device 112.